Process for manufacturing cement from blast-furnace slag.



' UN TED STATES- PATENT oFFiioE.

HEINRICH COLLOSEUS, OF BERLIN, GERMANY. PROCESS FOR .M uuFAc'TUmiie CEMENT F-aom BLAST-FURNACE sue;

To all. whomit may concern:

Be it known that I, HEINRICH QoLLosEUs,

' chemist and doctor of philosophy, a subject of the German Emperor, residin at 29 Praerstr'asse, in the city of Berlin, kingdom of russia, and German Empire, have invented a certain new and useful Process for Manufacturing Cement from Blast-Furnace Slag,

. of which the following'is a specification.

"This invention has reference to the manuiacture of cement from blast-furnace sla and it consists in a process wherein an addition of solutions of calcium salts, alumimum salts, and magnesium salts is madeto the slag,

according to its com osition, on the discharge of the slag from the last-furnace-fihat is to say, while it is yet in a liquid condition.

It'is a well-known fact that. blast-furnace slag, both the flourlike powder as well as the powdered granulated slag, possesses hydraulic qualities; but these powders will set only after several days and either do not attain at all the strength required of cement or, in thecase of particularly favorable compositions of slags, only after some months, so that they cannot be regarded as cements proper, practically speaking.

- My present invention consists in. introducing into the liquid blast-furnace slag salts of lime, of alumina, or of magnesia, in solution,

one or more of these, according to the pro or- .tion of lime, alumina, magnesia, and si icie acid contained in the slag and according to the hydraulic qualities dependent thereon.

The process is carried out as follows: The

stream of liquidslag when it runs out from the blast-furnace is finely distributed, and at the same time an aqueous solution of'calcium salts, of alum;- of sulfateof magnesia, or of "any other salt. or salts of one or more of these three metalsis allowed to act upon this finelydistributed slag. Water-vapor will then be evolved and also small quantities of vapors of sulfur dioxid formed by oxidation. The

sulfid contained in the blast-furnace slag, so

-.--as to form the valuable calcium sulfate.

The liberated water serves at the same time for the rapid cooling of slag, and more Specification'of Letters Patent.

. Application filed March 22,1905. Serial H9. 251.446-

' sents akind of clinker.

Hatented. nee. 11, 1906.

- particularly with iron-foundryslags, which are 'very rich in lime and which Without this 'rapid cooling would become disintegrated and form a flour, the so-ealled smelters flour. It also produces the eiiect of causing such slag toresist the action of air and repre- The vapor produced from the aqueous solution by the contact with the hot slag is a very efficient agent 1n efiectinga disinte ration of the slag and incorporating the sa ts with the hot slag. The dissociation which is thereby set up and the consequent liberation of the acid constituent of the salts is probably a great adjuvant in obtaining the peculiar degree of disintegration and the physical properties on which the value of cement, and of Portland cement in particular, depends. It is obvious that by a mere melting together'of the alkaline-earth constituents of the salts with the slag this object of the change of physical properties cannot be obtained, as it is not possible to have the salts so finely distributed or to produce the disintegration desired. The thus treated slag is distinguishedfrom the untreated slag,

apart from its chemical composition, in the following points as regards physical properties: first, as compared with the above-men'- tioned s'melters flour, disintegrated fiourlike slag, and water-granulated and air-treated slag, slags treated according to the'process herein described react considerably more readily; second, while the disintegrated flour, the dried water grannlated slag, and the airtreated slag either do not harden at all in most cases or only aftersome weeks, so as to form a kind of cement, the slag treated according to the process herein described exhibits the physical behavior of a good Portland cementtl1at' is to say, it sets within ten mmutes to six hours.

- Chemically speaking, ,the slag treated 210- cordlng to the process stated is distinguished from. smelters flour, disintegrated-slag flour, water-granulated slag, and slag that has un- IOC dergo'ne an air treatment. by the fact that the sulfid of lime, which is generally contamed 111 very large quantities in the smelters flour, m the water-granulated slag and in the air-treated slag is completely oxidized, or at least'the largest proportion of it, so as to form sulfate of lime. 73-

The amount of salts tobe used-varies with the composition of the particular slag. Ii, for example, blast-furnace slag is to be treated containing approximately from twentycentage of saltfor instance, up to ten per. cent-are injected, thus increasing the .)1'() six to thirty-two per cent. of silica, from I twelve to eighteen per cent. of alumina and iron, and from forty-live to fifty per cent. of

lime, it is su'ilicient to inject into the freshlyportion of salts in relation to the slag. l/v ith slags of approximately the composition herolnbefore mentioned I prefer to use sulfate of ma nesia alone iii-the majority of cases; but

Wit slags oi'iliflerent composition the best salt or combihation of salts for producing the desired resti'lt can only be ascertained by experimentiv If the slag is thick in flowing or is not perfiihtly liquid, it is desirable to reduce the percentage of solution used, at the same time increasing its strength in proportion. The object of this is not to cool the slag too much in the operation.

' I am aware that salts, and in particular so dium salts orgypsuin, have been added to hot liquid slag in a dry state in order to remove some impurities of the slag by mutual decomposition and. subsequent skimming oil the products of ('lecomposition. This is, however, entirely different from my invention, inasmuch as in my'invention the action depends mainly on a change of physical properties, as a)ove outlined, and upon the very fine state of distribution of the salts and disintegration of the slag, d no to the fact Cii'adding the salts in aqueous solution, while "the chemical reactions which are set up are also entirely difl'crcnt from those set up by the melting together of the reagents with the l am also aware that attempts have been made to improve-the uality of slag cement by treating molten ut not necessarily freshly-prepared-andvery highly heated slag with'a mixture of lime and chlorid of lime, in which the lime was greatly in excess of the chlorid of lime, so as to form a paste of lime containing a small percentage of chlorid of lime, in order to increase the amount of lime to be incorporated with the slag; but this also is not the object of my invention, which aims to produce a finished perfect cement semis without any subsequent addition of lime to the-molten slag and merely by the physical changes set'u by the dissociation produced upon the addition of the small quantities of solutions of salts of the alkaline earths and hot liquid. blast-furnace slag with a solution,

of any.water-soluble salt of the earthy oxidformmg metals and without any further ad dition- 2-. The process of manufacturing cement from blast-furnace slag which consists in act.- ing uponfreshly-1)repared hot liquid blastfurnaoeslag with relatively small quantities of the solution of any water-soluble salt of the earthy oxid-fori'ning metals and without any further addition.

3. The process of manufacturing cement from blast-furnace slag which consists in actingupon freshly-prepared hot liquid blastfurnace slag with a solution of any Watersoluble salt of the earthy oXid-forming metals, the slag being largely in excess of said solution, and without any further addition, and then allowingthe product to cool.

4. The process of manufacturing cement from blast-furnace slag which consists in acting upon freshly-prepared hot liquid blastfurnace slag with a solution of any watersoluble salt. of the earthy oxid-forming metals, most deficient in the composition of the slag, the slag being largely in excess, and without any further addition andallowing .the product to cool.

5. The process of manufacturing cement from blast-furnace slag which consists-in acting upon freshly-prepared hot liquid blastfurnace slag with so much of a solution of any water-soluble salt-of the earthy oxid-forming metals, the slag being largely in excess,-as to avoid chilling of the slag during the operation, and. without any further addition, and then allowing the product to cool. i

In witness whereof I have hereunto signed my name, this25th da of February, 1905, in the presence of two su Jscribing witnesses.

' HEINRICH. QOLLOSEUS.

I/Vitnesses IIENRY Hrsrnn, WoLDnnAn lilaurr. 

